Our garden wildlife pond has become, fairly rapidly, full of green slime...horrid wispy (and more solid) trails, like veils under the surface and floating islands. The surface is also covered by bubbles - the bottom of the pond seems to be fermenting! Last year there was masses of oxygenating pond weed in the deeper half but it's as if it's all died and is decomposing.

I know there's a fair amount of sludge at the bottom, and yes, we have at times allowed our ducks to have access, tho it's been mostly duck-free for over a year. The shallower half of the pond has a good coverage of pond plants which seem to be fine, albeit with much duckweed amongst the foliage. There are loads of newts.

Any ideas, pond-people???

Hairyloon

Joined: 20 Nov 2008Posts: 15174Location: Today I are mostly being in Yorkshire.

Posted: Fri Apr 07, 17 3:55 pm Post subject:

If there are newts then the water can't be too unpleasant.
Bubbles may be methane from anaerobic decomposition at the bottom: isn't necessarily a problem...

buzzy

Joined: 04 Jan 2011Posts: 3469Location: In a small wood on the edge of the Huntingdonshire Wolds

Posted: Fri Apr 07, 17 6:15 pm Post subject:

Sounds as if it's blanket weed, which is unsightly but not a necessarily a serious problem. The trouble with removing it is that you tend to drag a lot of other small creatures out with it, which is not a good idea, but if you do want to rake it out, leave the rakings close to the side of the pond so that things can crawl back in the water,

Some people suggest twirling a bamboo cane round and round and the weed should stick to the cane and allow you to pull out small amounts at a time, but I've never done it this way.

You can buy lots of products for getting rid of blanket weed, and spend lots of money. I have not tried any of them so can't speak for their efficacy, but will just say caveat emptor.

Henry

buzzy

Joined: 04 Jan 2011Posts: 3469Location: In a small wood on the edge of the Huntingdonshire Wolds

Sounds as if it's blanket weed, which is unsightly but not a necessarily a serious problem. The trouble with removing it is that you tend to drag a lot of other small creatures out with it, which is not a good idea, but if you do want to rake it out, leave the rakings close to the side of the pond so that things can crawl back in the water,

Some people suggest twirling a bamboo cane round and round and the weed should stick to the cane and allow you to pull out small amounts at a time, but I've never done it this way.

You can buy lots of products for getting rid of blanket weed, and spend lots of money. I have not tried any of them so can't speak for their efficacy, but will just say caveat emptor.

Henry

Chemicals can work as a quick fix but you have an underlying problem. Too much phosphates in there, most likely. Are you topping it off with tap water? Run off water from the grass? Over feeding?

It may not be fixable if it's run off. Physically clear it out, hit it with snatch of chemicals and install a filter with UV and it'll run crystal clear.

The problems it can bring are removing the oxygen from the water and, if it dies suddenly and isn't removed a huge spike in nitrates, them ammonia, which will kill livestock.

Eta: if plants are dying it's releasing phosphates and organically allowing more to grow. Physically clear a ton out.

Perhaps others can confirm, but I think barley straw is used to get rid of blanket weed. Think it absorbs the things that cause it to form and in addition it is a non-chemical method, so shouldn't upset the newts. Agree with what all the others have said too.

We dug a garden pond and newts appeared the following spring when there was very little in it. We have very little water up here, and think we intercepted them on their way to their former pond. We have had them ever since.